/*-
* Copyright (c) 2002-2007 Sam Leffler, Errno Consulting
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/net80211/ieee80211_crypto_tkip.c,v 1.13 2007/06/11 03:36:54 sam Exp $");

/*
* IEEE 802.11i TKIP crypto support.
*
* Part of this module is derived from similar code in the Host
* AP driver. The code is used with the consent of the author and
* it's license is included below.
*/
#include <sys/param.h>
#include <sys/systm.h> 
#include <sys/mbuf.h>   
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/endian.h>

#include <sys/socket.h>

#include <net/if.h>
#include <net/if_media.h>
#include <net/ethernet.h>

#include <net80211/ieee80211_var.h>

static  void *tkip_attach(struct ieee80211com *, struct ieee80211_key *);
static  void tkip_detach(struct ieee80211_key *);
static  int tkip_setkey(struct ieee80211_key *);
static  int tkip_encap(struct ieee80211_key *, struct mbuf *m, uint8_t keyid);
static  int tkip_enmic(struct ieee80211_key *, struct mbuf *, int);
static  int tkip_decap(struct ieee80211_key *, struct mbuf *, int);
static  int tkip_demic(struct ieee80211_key *, struct mbuf *, int);

static const struct ieee80211_cipher tkip  = {
.ic_name        = "TKIP",
.ic_cipher      = IEEE80211_CIPHER_TKIP,
.ic_header      = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN +
IEEE80211_WEP_EXTIVLEN,
.ic_trailer     = IEEE80211_WEP_CRCLEN,
.ic_miclen      = IEEE80211_WEP_MICLEN,
.ic_attach      = tkip_attach,
.ic_detach      = tkip_detach,
.ic_setkey      = tkip_setkey,
.ic_encap       = tkip_encap,
.ic_decap       = tkip_decap,
.ic_enmic       = tkip_enmic,
.ic_demic       = tkip_demic,
};

typedef uint8_t u8;
typedef uint16_t u16;
typedef uint32_t __u32;
typedef uint32_t u32;
#define memmove(dst, src, n)    ovbcopy(src, dst, n)

struct tkip_ctx {
struct ieee80211com *tc_ic;     /* for diagnostics */

u16     tx_ttak[5];
int     tx_phase1_done;
u8      tx_rc4key[16];          /* XXX for test module; make locals? */

u16     rx_ttak[5];
int     rx_phase1_done;
u8      rx_rc4key[16];          /* XXX for test module; make locals? */
uint64_t rx_rsc;                /* held until MIC verified */
};

static  void michael_mic(struct tkip_ctx *, const u8 *key,
struct mbuf *m, u_int off, size_t data_len,
u8 mic[IEEE80211_WEP_MICLEN]);
static  int tkip_encrypt(struct tkip_ctx *, struct ieee80211_key *,
struct mbuf *, int hdr_len);
static  int tkip_decrypt(struct tkip_ctx *, struct ieee80211_key *,
struct mbuf *, int hdr_len);

/* number of references from net80211 layer */
static  int nrefs = 0;

static void *
tkip_attach(struct ieee80211com *ic, struct ieee80211_key *k)
{
struct tkip_ctx *ctx;

MALLOC(ctx, struct tkip_ctx *, sizeof(struct tkip_ctx),
M_DEVBUF, M_NOWAIT | M_ZERO);
if (ctx == NULL) {
ic->ic_stats.is_crypto_nomem++;
return NULL;
}

ctx->tc_ic = ic;
nrefs++;                        /* NB: we assume caller locking */
return ctx;
}

static void
tkip_detach(struct ieee80211_key *k)
{
struct tkip_ctx *ctx = k->wk_private;

FREE(ctx, M_DEVBUF);
KASSERT(nrefs > 0, ("imbalanced attach/detach"));
nrefs--;                        /* NB: we assume caller locking */
}

static int
tkip_setkey(struct ieee80211_key *k)
{
struct tkip_ctx *ctx = k->wk_private;

if (k->wk_keylen != (128/NBBY)) {
(void) ctx;             /* XXX */
IEEE80211_DPRINTF(ctx->tc_ic, IEEE80211_MSG_CRYPTO,
"%s: Invalid key length %u, expecting %u\n",
__func__, k->wk_keylen, 128/NBBY);
return 0;
}
k->wk_keytsc = 1;               /* TSC starts at 1 */
return 1;
}

/*
* Add privacy headers and do any s/w encryption required.
*/
static int
tkip_encap(struct ieee80211_key *k, struct mbuf *m, uint8_t keyid)
{
struct tkip_ctx *ctx = k->wk_private;
struct ieee80211com *ic = ctx->tc_ic;
uint8_t *ivp;
int hdrlen;

/*
* Handle TKIP counter measures requirement.
*/
if (ic->ic_flags & IEEE80211_F_COUNTERM) {
#ifdef IEEE80211_DEBUG
struct ieee80211_frame *wh = mtod(m, struct ieee80211_frame *);
#endif

IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
"[%s] Discard frame due to countermeasures (%s)\n",
ether_sprintf(wh->i_addr2), __func__);
ic->ic_stats.is_crypto_tkipcm++;
return 0;
}
hdrlen = ieee80211_hdrspace(ic, mtod(m, void *));

/*
* Copy down 802.11 header and add the IV, KeyID, and ExtIV.
*/
M_PREPEND(m, tkip.ic_header, M_NOWAIT);
if (m == NULL)
return 0;
ivp = mtod(m, uint8_t *);
memmove(ivp, ivp + tkip.ic_header, hdrlen);
ivp += hdrlen;

ivp[0] = k->wk_keytsc >> 8;             /* TSC1 */
ivp[1] = (ivp[0] | 0x20) & 0x7f;        /* WEP seed */
ivp[2] = k->wk_keytsc >> 0;             /* TSC0 */
ivp[3] = keyid | IEEE80211_WEP_EXTIV;   /* KeyID | ExtID */
ivp[4] = k->wk_keytsc >> 16;            /* TSC2 */
ivp[5] = k->wk_keytsc >> 24;            /* TSC3 */
ivp[6] = k->wk_keytsc >> 32;            /* TSC4 */
ivp[7] = k->wk_keytsc >> 40;            /* TSC5 */

/*
* Finally, do software encrypt if neeed.
*/
if (k->wk_flags & IEEE80211_KEY_SWCRYPT) {
if (!tkip_encrypt(ctx, k, m, hdrlen))
return 0;
/* NB: tkip_encrypt handles wk_keytsc */
} else
k->wk_keytsc++;

return 1;
}

/*
* Add MIC to the frame as needed.
*/
static int
tkip_enmic(struct ieee80211_key *k, struct mbuf *m, int force)
{
struct tkip_ctx *ctx = k->wk_private;

if (force || (k->wk_flags & IEEE80211_KEY_SWMIC)) {
struct ieee80211_frame *wh = mtod(m, struct ieee80211_frame *);
struct ieee80211com *ic = ctx->tc_ic;
int hdrlen;
uint8_t mic[IEEE80211_WEP_MICLEN];

ic->ic_stats.is_crypto_tkipenmic++;

hdrlen = ieee80211_hdrspace(ic, wh);

michael_mic(ctx, k->wk_txmic,
m, hdrlen, m->m_pkthdr.len - hdrlen, mic);
return m_append(m, tkip.ic_miclen, mic);
}
return 1;
}

static __inline uint64_t
READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5)
{
uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24);
uint16_t iv16 = (b4 << 0) | (b5 << 8);
return (((uint64_t)iv16) << 32) | iv32;
}

/*
* Validate and strip privacy headers (and trailer) for a
* received frame.  If necessary, decrypt the frame using
* the specified key.
*/
static int
tkip_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen)
{
struct tkip_ctx *ctx = k->wk_private;
struct ieee80211com *ic = ctx->tc_ic;
struct ieee80211_frame *wh;
uint8_t *ivp;

/*
* Header should have extended IV and sequence number;
* verify the former and validate the latter.
*/
wh = mtod(m, struct ieee80211_frame *);
ivp = mtod(m, uint8_t *) + hdrlen;
if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) {
/*
* No extended IV; discard frame.
*/
IEEE80211_DPRINTF(ctx->tc_ic, IEEE80211_MSG_CRYPTO,
"[%s] missing ExtIV for TKIP cipher\n",
ether_sprintf(wh->i_addr2));
ctx->tc_ic->ic_stats.is_rx_tkipformat++;
return 0;
}
/*
* Handle TKIP counter measures requirement.
*/
if (ic->ic_flags & IEEE80211_F_COUNTERM) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
"[%s] discard frame due to countermeasures (%s)\n",
ether_sprintf(wh->i_addr2), __func__);
ic->ic_stats.is_crypto_tkipcm++;
return 0;
}

ctx->rx_rsc = READ_6(ivp[2], ivp[0], ivp[4], ivp[5], ivp[6], ivp[7]);
if (ctx->rx_rsc <= k->wk_keyrsc) {
/*
* Replay violation; notify upper layer.
*/
ieee80211_notify_replay_failure(ctx->tc_ic, wh, k, ctx->rx_rsc);
ctx->tc_ic->ic_stats.is_rx_tkipreplay++;
return 0;
}
/*
* NB: We can't update the rsc in the key until MIC is verified.
*
* We assume we are not preempted between doing the check above
* and updating wk_keyrsc when stripping the MIC in tkip_demic.
* Otherwise we might process another packet and discard it as
* a replay.
*/

/*
* Check if the device handled the decrypt in hardware.
* If so we just strip the header; otherwise we need to
* handle the decrypt in software.
*/
if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) &&
!tkip_decrypt(ctx, k, m, hdrlen))
return 0;

/*
* Copy up 802.11 header and strip crypto bits.
*/
memmove(mtod(m, uint8_t *) + tkip.ic_header, mtod(m, void *), hdrlen);
m_adj(m, tkip.ic_header);
m_adj(m, -tkip.ic_trailer);

return 1;
}

/*
* Verify and strip MIC from the frame.
*/
static int
tkip_demic(struct ieee80211_key *k, struct mbuf *m, int force)
{
struct tkip_ctx *ctx = k->wk_private;

if (force || (k->wk_flags & IEEE80211_KEY_SWMIC)) {
struct ieee80211_frame *wh = mtod(m, struct ieee80211_frame *);
struct ieee80211com *ic = ctx->tc_ic;
int hdrlen = ieee80211_hdrspace(ic, wh);
u8 mic[IEEE80211_WEP_MICLEN];
u8 mic0[IEEE80211_WEP_MICLEN];

ic->ic_stats.is_crypto_tkipdemic++;

michael_mic(ctx, k->wk_rxmic, 
m, hdrlen, m->m_pkthdr.len - (hdrlen + tkip.ic_miclen),
mic);
m_copydata(m, m->m_pkthdr.len - tkip.ic_miclen,
tkip.ic_miclen, mic0);
if (memcmp(mic, mic0, tkip.ic_miclen)) {
/* NB: 802.11 layer handles statistic and debug msg */
ieee80211_notify_michael_failure(ic, wh,
k->wk_rxkeyix != IEEE80211_KEYIX_NONE ?
k->wk_rxkeyix : k->wk_keyix);
return 0;
}
}
/*
* Strip MIC from the tail.
*/
m_adj(m, -tkip.ic_miclen);

/*
* Ok to update rsc now that MIC has been verified.
*/
k->wk_keyrsc = ctx->rx_rsc;

return 1;
}

/*
* Host AP crypt: host-based TKIP encryption implementation for Host AP driver
*
* Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation. See README and COPYING for
* more details.
*
* Alternatively, this software may be distributed under the terms of BSD
* license.
*/

static const __u32 crc32_table[256] = {
0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
0x2d02ef8dL
};

static __inline u16 RotR1(u16 val)
{
return (val >> 1) | (val << 15);
}

static __inline u8 Lo8(u16 val)
{
return val & 0xff;
}

static __inline u8 Hi8(u16 val)
{
return val >> 8;
}

static __inline u16 Lo16(u32 val)
{
return val & 0xffff;
}

static __inline u16 Hi16(u32 val)
{
return val >> 16;
}

static __inline u16 Mk16(u8 hi, u8 lo)
{
return lo | (((u16) hi) << 8);
}

static __inline u16 Mk16_le(const u16 *v)
{
return le16toh(*v);
}

static const u16 Sbox[256] = {
0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
};

static __inline u16 _S_(u16 v)
{
u16 t = Sbox[Hi8(v)];
return Sbox[Lo8(v)] ^ ((t << 8) | (t >> 8));
}

#define PHASE1_LOOP_COUNT 8

static void tkip_mixing_phase1(u16 *TTAK, const u8 *TK, const u8 *TA, u32 IV32)
{
int i, j;

/* Initialize the 80-bit TTAK from TSC (IV32) and TA[0..5] */
TTAK[0] = Lo16(IV32);
TTAK[1] = Hi16(IV32);
TTAK[2] = Mk16(TA[1], TA[0]);
TTAK[3] = Mk16(TA[3], TA[2]);
TTAK[4] = Mk16(TA[5], TA[4]);

for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
j = 2 * (i & 1);
TTAK[0] += _S_(TTAK[4] ^ Mk16(TK[1 + j], TK[0 + j]));
TTAK[1] += _S_(TTAK[0] ^ Mk16(TK[5 + j], TK[4 + j]));
TTAK[2] += _S_(TTAK[1] ^ Mk16(TK[9 + j], TK[8 + j]));
TTAK[3] += _S_(TTAK[2] ^ Mk16(TK[13 + j], TK[12 + j]));
TTAK[4] += _S_(TTAK[3] ^ Mk16(TK[1 + j], TK[0 + j])) + i;
}
}

#ifndef _BYTE_ORDER
#error "Don't know native byte order"
#endif

static void tkip_mixing_phase2(u8 *WEPSeed, const u8 *TK, const u16 *TTAK,
u16 IV16)
{
/* Make temporary area overlap WEP seed so that the final copy can be
* avoided on little endian hosts. */
u16 *PPK = (u16 *) &WEPSeed[4];

/* Step 1 - make copy of TTAK and bring in TSC */
PPK[0] = TTAK[0];
PPK[1] = TTAK[1];
PPK[2] = TTAK[2];
PPK[3] = TTAK[3];
PPK[4] = TTAK[4];
PPK[5] = TTAK[4] + IV16;

/* Step 2 - 96-bit bijective mixing using S-box */
PPK[0] += _S_(PPK[5] ^ Mk16_le((const u16 *) &TK[0]));
PPK[1] += _S_(PPK[0] ^ Mk16_le((const u16 *) &TK[2]));
PPK[2] += _S_(PPK[1] ^ Mk16_le((const u16 *) &TK[4]));
PPK[3] += _S_(PPK[2] ^ Mk16_le((const u16 *) &TK[6]));
PPK[4] += _S_(PPK[3] ^ Mk16_le((const u16 *) &TK[8]));
PPK[5] += _S_(PPK[4] ^ Mk16_le((const u16 *) &TK[10]));

PPK[0] += RotR1(PPK[5] ^ Mk16_le((const u16 *) &TK[12]));
PPK[1] += RotR1(PPK[0] ^ Mk16_le((const u16 *) &TK[14]));
PPK[2] += RotR1(PPK[1]);
PPK[3] += RotR1(PPK[2]);
PPK[4] += RotR1(PPK[3]);
PPK[5] += RotR1(PPK[4]);

/* Step 3 - bring in last of TK bits, assign 24-bit WEP IV value
* WEPSeed[0..2] is transmitted as WEP IV */
WEPSeed[0] = Hi8(IV16);
WEPSeed[1] = (Hi8(IV16) | 0x20) & 0x7F;
WEPSeed[2] = Lo8(IV16);
WEPSeed[3] = Lo8((PPK[5] ^ Mk16_le((const u16 *) &TK[0])) >> 1);

#if _BYTE_ORDER == _BIG_ENDIAN
{
int i;
for (i = 0; i < 6; i++)
PPK[i] = (PPK[i] << 8) | (PPK[i] >> 8);
}
#endif
}

static void
wep_encrypt(u8 *key, struct mbuf *m0, u_int off, size_t data_len,
uint8_t icv[IEEE80211_WEP_CRCLEN])
{
u32 i, j, k, crc;
size_t buflen;
u8 S[256];
u8 *pos;
struct mbuf *m;
#define S_SWAP(a,b) do { u8 t = S[a]; S[a] = S[b]; S[b] = t; } while(0)

/* Setup RC4 state */
for (i = 0; i < 256; i++)
S[i] = i;
j = 0;
for (i = 0; i < 256; i++) {
j = (j + S[i] + key[i & 0x0f]) & 0xff;
S_SWAP(i, j);
}

/* Compute CRC32 over unencrypted data and apply RC4 to data */
crc = ~0;
i = j = 0;
m = m0;
pos = mtod(m, uint8_t *) + off;
buflen = m->m_len - off;
for (;;) {
if (buflen > data_len)
buflen = data_len;
data_len -= buflen;
for (k = 0; k < buflen; k++) {
crc = crc32_table[(crc ^ *pos) & 0xff] ^ (crc >> 8);
i = (i + 1) & 0xff;
j = (j + S[i]) & 0xff;
S_SWAP(i, j);
*pos++ ^= S[(S[i] + S[j]) & 0xff];
}
m = m->m_next;
if (m == NULL) {
KASSERT(data_len == 0,
("out of buffers with data_len %zu\n", data_len));
break;
}
pos = mtod(m, uint8_t *);
buflen = m->m_len;
}
crc = ~crc;

/* Append little-endian CRC32 and encrypt it to produce ICV */
icv[0] = crc;
icv[1] = crc >> 8;
icv[2] = crc >> 16;
icv[3] = crc >> 24;
for (k = 0; k < IEEE80211_WEP_CRCLEN; k++) {
i = (i + 1) & 0xff;
j = (j + S[i]) & 0xff;
S_SWAP(i, j);
icv[k] ^= S[(S[i] + S[j]) & 0xff];
}
}

static int
wep_decrypt(u8 *key, struct mbuf *m, u_int off, size_t data_len)
{
u32 i, j, k, crc;
u8 S[256];
u8 *pos, icv[4];
size_t buflen;

/* Setup RC4 state */
for (i = 0; i < 256; i++)
S[i] = i;
j = 0;
for (i = 0; i < 256; i++) {
j = (j + S[i] + key[i & 0x0f]) & 0xff;
S_SWAP(i, j);
}

/* Apply RC4 to data and compute CRC32 over decrypted data */
crc = ~0;
i = j = 0;
pos = mtod(m, uint8_t *) + off;
buflen = m->m_len - off;
for (;;) {
if (buflen > data_len)
buflen = data_len;
data_len -= buflen;
for (k = 0; k < buflen; k++) {
i = (i + 1) & 0xff;
j = (j + S[i]) & 0xff;
S_SWAP(i, j);
*pos ^= S[(S[i] + S[j]) & 0xff];
crc = crc32_table[(crc ^ *pos) & 0xff] ^ (crc >> 8);
pos++;
}
m = m->m_next;
if (m == NULL) {
KASSERT(data_len == 0,
("out of buffers with data_len %zu\n", data_len));
break;
}
pos = mtod(m, uint8_t *);
buflen = m->m_len;
}
crc = ~crc;

/* Encrypt little-endian CRC32 and verify that it matches with the
* received ICV */
icv[0] = crc;
icv[1] = crc >> 8;
icv[2] = crc >> 16;
icv[3] = crc >> 24;
for (k = 0; k < 4; k++) {
i = (i + 1) & 0xff;
j = (j + S[i]) & 0xff;
S_SWAP(i, j);
if ((icv[k] ^ S[(S[i] + S[j]) & 0xff]) != *pos++) {
/* ICV mismatch - drop frame */
return -1;
}
}

return 0;
}


static __inline u32 rotl(u32 val, int bits)
{
return (val << bits) | (val >> (32 - bits));
}


static __inline u32 rotr(u32 val, int bits)
{
return (val >> bits) | (val << (32 - bits));
}


static __inline u32 xswap(u32 val)
{
return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8);
}


#define michael_block(l, r)     \
do {                            \
r ^= rotl(l, 17);       \
l += r;                 \
r ^= xswap(l);          \
l += r;                 \
r ^= rotl(l, 3);        \
l += r;                 \
r ^= rotr(l, 2);        \
l += r;                 \
} while (0)


static __inline u32 get_le32_split(u8 b0, u8 b1, u8 b2, u8 b3)
{
return b0 | (b1 << 8) | (b2 << 16) | (b3 << 24);
}

static __inline u32 get_le32(const u8 *p)
{
return get_le32_split(p[0], p[1], p[2], p[3]);
}


static __inline void put_le32(u8 *p, u32 v)
{
p[0] = v;
p[1] = v >> 8;
p[2] = v >> 16;
p[3] = v >> 24;
}

/*
* Craft pseudo header used to calculate the MIC.
*/
static void
michael_mic_hdr(const struct ieee80211_frame *wh0, uint8_t hdr[16])
{
const struct ieee80211_frame_addr4 *wh =
(const struct ieee80211_frame_addr4 *) wh0;

switch (wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) {
case IEEE80211_FC1_DIR_NODS:
IEEE80211_ADDR_COPY(hdr, wh->i_addr1); /* DA */
IEEE80211_ADDR_COPY(hdr + IEEE80211_ADDR_LEN, wh->i_addr2);
break;
case IEEE80211_FC1_DIR_TODS:
IEEE80211_ADDR_COPY(hdr, wh->i_addr3); /* DA */
IEEE80211_ADDR_COPY(hdr + IEEE80211_ADDR_LEN, wh->i_addr2);
break;
case IEEE80211_FC1_DIR_FROMDS:
IEEE80211_ADDR_COPY(hdr, wh->i_addr1); /* DA */
IEEE80211_ADDR_COPY(hdr + IEEE80211_ADDR_LEN, wh->i_addr3);
break;
case IEEE80211_FC1_DIR_DSTODS:
IEEE80211_ADDR_COPY(hdr, wh->i_addr3); /* DA */
IEEE80211_ADDR_COPY(hdr + IEEE80211_ADDR_LEN, wh->i_addr4);
break;
}

if (wh->i_fc[0] & IEEE80211_FC0_SUBTYPE_QOS) {
const struct ieee80211_qosframe *qwh =
(const struct ieee80211_qosframe *) wh;
hdr[12] = qwh->i_qos[0] & IEEE80211_QOS_TID;
} else
hdr[12] = 0;
hdr[13] = hdr[14] = hdr[15] = 0; /* reserved */
}

static void
michael_mic(struct tkip_ctx *ctx, const u8 *key,
struct mbuf *m, u_int off, size_t data_len,
u8 mic[IEEE80211_WEP_MICLEN])
{
uint8_t hdr[16];
u32 l, r;
const uint8_t *data;
u_int space;

michael_mic_hdr(mtod(m, struct ieee80211_frame *), hdr);

l = get_le32(key);
r = get_le32(key + 4);

/* Michael MIC pseudo header: DA, SA, 3 x 0, Priority */
l ^= get_le32(hdr);
michael_block(l, r);
l ^= get_le32(&hdr[4]);
michael_block(l, r);
l ^= get_le32(&hdr[8]);
michael_block(l, r);
l ^= get_le32(&hdr[12]);
michael_block(l, r);

/* first buffer has special handling */
data = mtod(m, const uint8_t *) + off;
space = m->m_len - off;
for (;;) {
if (space > data_len)
space = data_len;
/* collect 32-bit blocks from current buffer */
while (space >= sizeof(uint32_t)) {
l ^= get_le32(data);
michael_block(l, r);
data += sizeof(uint32_t), space -= sizeof(uint32_t);
data_len -= sizeof(uint32_t);
}
if (data_len < sizeof(uint32_t))
break;
m = m->m_next;
if (m == NULL) {
KASSERT(0, ("out of data, data_len %zu\n", data_len));
break;
}
if (space != 0) {
const uint8_t *data_next;
/*
* Block straddles buffers, split references.
*/
data_next = mtod(m, const uint8_t *);
KASSERT(m->m_len >= sizeof(uint32_t) - space,
("not enough data in following buffer, "
"m_len %u need %zu\n", m->m_len,
sizeof(uint32_t) - space));
switch (space) {
case 1:
l ^= get_le32_split(data[0], data_next[0],
data_next[1], data_next[2]);
data = data_next + 3;
space = m->m_len - 3;
break;
case 2:
l ^= get_le32_split(data[0], data[1],
data_next[0], data_next[1]);
data = data_next + 2;
space = m->m_len - 2;
break;
case 3:
l ^= get_le32_split(data[0], data[1],
data[2], data_next[0]);
data = data_next + 1;
space = m->m_len - 1;
break;
}
michael_block(l, r);
data_len -= sizeof(uint32_t);
} else {
/*
* Setup for next buffer.
*/
data = mtod(m, const uint8_t *);
space = m->m_len;
}
}
/* Last block and padding (0x5a, 4..7 x 0) */
switch (data_len) {
case 0:
l ^= get_le32_split(0x5a, 0, 0, 0);
break;
case 1:
l ^= get_le32_split(data[0], 0x5a, 0, 0);
break;
case 2:
l ^= get_le32_split(data[0], data[1], 0x5a, 0);
break;
case 3:
l ^= get_le32_split(data[0], data[1], data[2], 0x5a);
break;
}
michael_block(l, r);
/* l ^= 0; */
michael_block(l, r);

put_le32(mic, l);
put_le32(mic + 4, r);
}

static int
tkip_encrypt(struct tkip_ctx *ctx, struct ieee80211_key *key,
struct mbuf *m, int hdrlen)
{
struct ieee80211_frame *wh;
uint8_t icv[IEEE80211_WEP_CRCLEN];

ctx->tc_ic->ic_stats.is_crypto_tkip++;

wh = mtod(m, struct ieee80211_frame *);
if (!ctx->tx_phase1_done) {
tkip_mixing_phase1(ctx->tx_ttak, key->wk_key, wh->i_addr2,
(u32)(key->wk_keytsc >> 16));
ctx->tx_phase1_done = 1;
}
tkip_mixing_phase2(ctx->tx_rc4key, key->wk_key, ctx->tx_ttak,
(u16) key->wk_keytsc);

wep_encrypt(ctx->tx_rc4key,
m, hdrlen + tkip.ic_header,
m->m_pkthdr.len - (hdrlen + tkip.ic_header),
icv);
(void) m_append(m, IEEE80211_WEP_CRCLEN, icv);  /* XXX check return */

key->wk_keytsc++;
if ((u16)(key->wk_keytsc) == 0)
ctx->tx_phase1_done = 0;
return 1;
}

static int
tkip_decrypt(struct tkip_ctx *ctx, struct ieee80211_key *key,
struct mbuf *m, int hdrlen)
{
struct ieee80211_frame *wh;
u32 iv32;
u16 iv16;

ctx->tc_ic->ic_stats.is_crypto_tkip++;

wh = mtod(m, struct ieee80211_frame *);
/* NB: tkip_decap already verified header and left seq in rx_rsc */
iv16 = (u16) ctx->rx_rsc;
iv32 = (u32) (ctx->rx_rsc >> 16);

if (iv32 != (u32)(key->wk_keyrsc >> 16) || !ctx->rx_phase1_done) {
tkip_mixing_phase1(ctx->rx_ttak, key->wk_key,
wh->i_addr2, iv32);
ctx->rx_phase1_done = 1;
}
tkip_mixing_phase2(ctx->rx_rc4key, key->wk_key, ctx->rx_ttak, iv16);

/* NB: m is unstripped; deduct headers + ICV to get payload */
if (wep_decrypt(ctx->rx_rc4key,
m, hdrlen + tkip.ic_header,
m->m_pkthdr.len - (hdrlen + tkip.ic_header + tkip.ic_trailer))) {
if (iv32 != (u32)(key->wk_keyrsc >> 16)) {
/* Previously cached Phase1 result was already lost, so
* it needs to be recalculated for the next packet. */
ctx->rx_phase1_done = 0;
}
IEEE80211_DPRINTF(ctx->tc_ic, IEEE80211_MSG_CRYPTO,
"[%s] TKIP ICV mismatch on decrypt\n",
ether_sprintf(wh->i_addr2));
ctx->tc_ic->ic_stats.is_rx_tkipicv++;
return 0;
}
return 1;
}

/*
* Module glue.
*/
IEEE80211_CRYPTO_MODULE(tkip, 1);
